1. Field of the Invention
This invention relates to an improvement in the suspension system for vehicles equipped with an air-spring-assisted car-height adjusting mechanism.
2. Description of the Prior Art
Some suspension systems for vehicles are equipped with an air-spring-assisted car-height adjusting mechanism.
With this type of conventional suspension systems, however, it has been impossible to change the spring constant freely in accordance with the varying running conditions while maintaining a given car height. So, if the spring constant is preliminarily set at a lower level, the car body rolls and/or pitches heavily, with a resulting impairment of steering stability, when it is exposed to external force. If, on the other hand, the spring constant is set at a higher level to secure steering stability, riding comfort is reduced.
This type of suspension systems also has a modified version which comprises an auxiliary air-spring chamber of a given capacity connected to a main air-spring chamber and a switch valve interposed between the two air-spring chambers. When the switch valve is closed, a relatively large spring force is obtained by use of the air contained in the main air-spring chamber alone. When the switch valve is opened, a relatively small spring force is obtained by use of the air contained in the main and auxiliary air-spring chambers.
This modified version also has not been without shortcomings. Because the auxiliary air-spring chamber is positioned away from the suspension strut, it is necessary to secure a space to place the auxiliary air-spring chamber itself, a passage interconnecting the two air-spring chambers, and the switch valve. It is also necessary to provide some means to protect the interconnecting passage and switch valve.